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View Full Version : Head Porting.



COOKIE
05-13-2004, 06:22 PM
I'm thinking about having the head ported on my X. Anyone ever had any dealings with Duncan Racing? They want $495 for a full port and polish with a 3 angle valve job. They claim that I could see up to 35% increase over what I have now with my current setup. Who here can give me their impressions of how their bike felt before and after having port work done? Any feed back would be helpful.

Mobular
05-13-2004, 06:46 PM
At that cost, the job must be what is called here the stage 3 port job. It's a balls out affair, meant for strictly WOT top end power. The ports and runners are hogged out so large that low end response, if any is left, is minimal. I went with a stage 1 . Clean up the runners and smooth out the valve seat and guide bosses. Cost was fair, and power increase was good. It worked well with a mild cam, free flowing pipe and 10.25:1 piston. I could have gone all out, but I like to have the grunty bottom end!

The rule here is just like car cams, large is rarely the best! Use what will work with existing equipment, and build for the intended use.

COOKIE
05-13-2004, 08:32 PM
All out wide open power is what I'm after. The bike has plenty of low end to spare with the 425 kit and the 12:1 compression. But you say you did notice a difference with the porting that you did? Good. It's a good sign that I will too. Thanks for the info.